-slipper
Sure you can! Don't know for the life of me why nobody responded.
Id' recommend you not only enable WEP (Password), but also create an access control list to specifically allow the MAC addresses of only those authorized - so even if someone got the PW, they still couldn't even gain physical connection to the PW question.
Third, if this is a wireless only router - meaning you are not using it to NAT to wired computers, I'd check "Create Closed Network", to make your network invisible to snoops.
As for limiting bandwidth usage to a MAC address, I'm sure it can be done, but not near my AEBS to even play around with it right now. I'll see what I can find.